Existing hall call allocation systems and methods use criteria, such as waiting time, time to destination, energy consumption, and elevator usage, with neural networks, generic algorithms, and/or fuzzy logic to find an optimum solution for assigning a new hall call to one of a group of available elevator cars. These existing systems and methods generally fall into one of two categories: Estimate Time of Arrival (“ETA”) based systems and destination dispatch based systems.
Existing systems and methods often have shortcomings that limit their efficiencies. ETA based systems calculate the amount of time required for each available elevator to answer a new hall call. The elevator with the lowest time required to answer the call, i.e. the car that will arrive first, is assigned the new hall call. While ETA based systems have some advantages, they do not adequately evaluate the negative impact of a new hall call assignment on existing call assignments. For example, when a passenger enters a new hall call and it is accepted by an elevator car carrying existing passengers that are traveling to a floor beyond the floor where the newly assigned hall call was entered, the existing passengers will be delayed by the time needed to pick up the new passenger and depending upon the new passenger's desired destination, the existing passengers may be delayed by the time needed to drop off the new passenger.
Destination dispatch systems also have shortcomings. For example, they often require a destination input device at each elevator landing and usually have no call input devices in the elevator car. Because destination dispatch systems require entry devices at every elevator landing, they must make an instant call assignment and inform a waiting passenger which car to enter. This instant assignment does not permit an improved assignment if conditions change during the time period between call entry and car arrival. Thus, an elevator hall call assignment system and method that does not require destination entry devices at every elevator landing and that takes into account the delay that a new hall call assignment will have on existing passengers would greatly improve the elevator car.
Studies have suggested that the inconvenience of delay perceived by elevator passengers is based on the type of waiting they are subjected to in addition to the time delay. For example, passengers generally become impatient if they must wait more than thirty seconds to board an elevator and if they have to wait more than ninety seconds for the elevator to reach its destination. ETA systems attempt to reduce the overall waiting time required for passengers to reach their destination, but do not account for the differences in perceived inconvenience associated with different types of waiting. It would therefore be advantageous to provide an elevator system that accounts for these different types of waiting periods in dispatching elevators.